Crazy woman movie

Trying to find name of this movie In the movie there is a woman who says she got out of a relationship with a bad guy. She falls in love with this man who is married and they have an affair. she starts pretending to be in a relationship but the guy continues to try and get away from her. The wife of the man ends up dying and he states that the Woman did it. They put the woman under a lie detector or a truth serum and she doesnt say that she kills the wife. She says instead that her and the guy had a wonderful relationship and the cops are convinced that the man killed the wife when he didnt. he goes to jail at the end and she ends up meeting another guy before the movie ends